package Torello.Browser.JsonAST;

import Torello.JavaDoc.Annotations.LinkJavaSource;
import Torello.JavaDoc.Annotations.JDHeaderBackgroundImg;

import Torello.JSON.ReadJSON;

import Torello.Java.ReadOnly.ReadOnlySet;
import Torello.Java.ReadOnly.ReadOnlyTreeSet;

import Torello.Browser.CDPTypes;

import javax.json.JsonObject;
import java.io.IOException;
import java.util.Objects;


/**
 * Contains the data needed to represent a property, parameter or return value.
 * <EMBED CLASS='external-html' DATA-FILE-ID=AST_TREES>
 */
@JDHeaderBackgroundImg(EmbedTagFileID="AST_NODES_JDHBI")
public class PPR extends Entity implements java.io.Serializable
{
    // ********************************************************************************************
    // ********************************************************************************************
    // STATIC FINAL FIELDS
    // ********************************************************************************************
    // ********************************************************************************************


    /** <EMBED CLASS='external-html' DATA-FILE-ID=SVUID> */
    protected static final long serialVersionUID = 1;

    /**
     * The list of additional {@link JsonObject} properties that the parser should expect when
     * parsing {@code PPR} objects from the JSON CDP specification files.
     */
    protected static final ReadOnlySet<String> PPR_JSON_PROPERTIES =
        new ReadOnlyTreeSet<>(String::compareTo, "name", "$ref");


    // ********************************************************************************************
    // ********************************************************************************************
    // Constant & Final Instance-Fields (Set by the Constructor)
    // ********************************************************************************************
    // ********************************************************************************************


    /**
     * This is a "Back Pointer" to the {@link TCE} (either a {@link TypeNode}, {@link CommandNode}
     * or {@link EventNode}) that is the parent or owner of {@code 'this'} PPR instance.
     */
    public final TCE ownerTCE;

    /**
     * Expresses, explicitly, (without requiring an {@code 'instanceof'} operator), whether or not
     * {@code 'this'} instance repesents a property, a parameter or a return-value.
     * 
     * <EMBED CLASS='external-html' DATA-FILE-ID=PPR.which>
     */
    public final WhichPPR which;

    /**
     * This field is declared {@code final}, and contains the raw-{@code String} value which is
     * retrieved (during JSON parsing) from the {@code "$ref"} {@link JsonObject} property which
     * defines {@code 'this' PPR} instance 
     * 
     * <EMBED CLASS='external-html' DATA-FILE-ID=PPR.ref>
     */
    public final String ref;

    /**
     * This {@code String} is declared {@code final}, and contains the raw-{@code String} value
     * which is retrieved during the parsing of an {@code 'items'} {@link JsonObject} within this
     * {@code PPR} definition.
     * 
     * <EMBED CLASS='external-html' DATA-FILE-ID=PPR.refArray>
     */
    public final String refArray;


    // ********************************************************************************************
    // ********************************************************************************************
    // Non-Final Fields, set By the Linker
    // ********************************************************************************************
    // ********************************************************************************************


    private TypeNode    reference       = null;
    private TypeNode    referenceArray  = null;
    private String      ctas            = null;
    private byte        ctab            = 0;

    /**
     * Returns the value of the {@code private} field {@code 'reference'}; a field that represents
     * the resolved target of a {@code '$ref'} property.
     * 
     * <EMBED CLASS='external-html' DATA-FILE-ID=PPR.reference>
     */
    public final TypeNode reference() { return reference; }

    /**
     * Returns the value of the {@code private} field {@code 'referenceArray'}; a field that
     * represents the resolved target of a {@code '$ref'} property which was extracted from an
     * {@code 'items'} object.
     * 
     * <EMBED CLASS='external-html' DATA-FILE-ID=PPR.referenceArray>
     */
    public final TypeNode referenceArray() { return referenceArray; }

    /**
     * Returns the value of the private field {@code 'ctas'}; a field that represents the
     * "Computed Type as String" - the <B STYLE='color:red;'><I>Java Type of this PPR</I></B>, as a
     * {@code java.lang.String}).
     * 
     * <EMBED CLASS='external-html' DATA-FILE-ID=PPR.CTAS>
     * 
     * @see CTAB
     */
    public final String CTAS() { return ctas; }

    /**
     * Returns the value of the private field {@code 'ctab'}; a field that represents the "Computed
     * Type as Byte".
     * 
     * <EMBED CLASS='external-html' DATA-FILE-ID=PPR.CTAB>
     * 
     * @see CTAS
     * @see CDPTypes 
     */
    public final byte CTAB() { return ctab; }


    // ********************************************************************************************
    // ********************************************************************************************
    // Package-Private Setters; nethods not visible to callers from outside of Java-HTML
    // ********************************************************************************************
    // ********************************************************************************************


    // It is important to realize that 'reference' and 'referenceArray' must be assigned first,
    // if they are ever going to be assigned to anything other than null.

    private static final String LINK_ERROR_MSG = 
        "A value has already been assigned to the 'ctas' or 'ctab' fields.  These fields " +
        "contain the 'Computed Type', and once they have been assigned, reassigning a value " +
        "to field 'reference' or 'referenceArray' is not allowed.";

    void setReference(final TypeNode reference)
    {
        // This is a "Space Age UnreachableError" Check.
        if ((this.ctas != null) || (this.ctab != 0)) throw new LinkingStateError(LINK_ERROR_MSG);
        this.reference = reference;
    }

    void setReferenceArray(final TypeNode referenceArray)
    {
        // This is a "Space Age UnreachableError" Check.
        if ((this.ctas != null) || (this.ctab != 0)) throw new LinkingStateError(LINK_ERROR_MSG);
        this.referenceArray = referenceArray;
    }

    void setCTAS(final String ctas)
    {
        if ((this.ctas != null) || (this.ctab != 0)) throw new LinkingStateError
            ("'ctas' or 'ctab' have already been assigned.  They may not be reassigned.");

        this.ctas = ctas;
        this.ctab = CDPTypes.ctasToByte(ctas, reference != null, referenceArray != null);
    }


    // ********************************************************************************************
    // ********************************************************************************************
    // Constructor
    // ********************************************************************************************
    // ********************************************************************************************


    PPR(
            final TCE           ownerTCE,
            final JsonObject    jo,
            final WhichPPR      which,
            final int           index
        )
    {
        super(
            ownerTCE.ownerDomain,
            WhichEntity.ClassPPR,
            jo,
            index,
            PPR_JSON_PROPERTIES
        );

        this.ownerTCE   = ownerTCE;
        this.which      = which;

        // getString(JsonObject jo, String propertyName, boolean isOptional, boolean throwOnNull)
        this.ref = ReadJSON.getString(jo, "$ref", true, true);

        if ((this.typeProp == TypeProp.ARRAY) && (this.arrItemsTypeProp == null))
        {
            // getJsonObject(jo, propertyName, boolean isOptional, boolean throwOnNull)
            final JsonObject arrItemsProp = ReadJSON.getJsonObject(jo, "items", false, true);

            // getString jo, propertyName, boolean isOptional, boolean throwOnNull)
            this.refArray = ReadJSON.getString(arrItemsProp, "$ref", false, true);
        }

        else this.refArray = null;
    }


    // ********************************************************************************************
    // ********************************************************************************************
    // Cloneable, Comparable, Object
    // ********************************************************************************************
    // ********************************************************************************************


    /** Returns a {@code String} representation of {@code 'this'} instance. */
    @LinkJavaSource(handle="StringPPR")
    public String toString()
    { return StringPPR.get(this); }

    /**
     * Returns a brief (shorter than the {@link toString}a output)) {@code String} summary of
     * {@code 'this'} instance.
     */
    public String toStringShort()
    {
        return
            this.ownerDomain.ownerAPI.name + '.' +  // API-Name
            this.ownerDomain.name + '.' +           // Domain-Name
            this.ownerTCE.name + '.' +              // TCE-Name
            this.name + ' ' +                       // PPR-Name
            "[WhichTCE." + this.ownerTCE.which + ", WhichPPR." + this.which + ']';
    }
}